// Copyright (C) 2012 Yury Bychenkov (http://bychenkov.com).
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//  - Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//  - Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//  - Neither the name of Yury Bychenkov nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

namespace NumberUtil {

inline int numberOfLeadingZeroes(uint8 value) {
    if (value == 0) return 8;
    int n = 0;
    if ((value & 0xF0) == 0) { n += 4; value <<= 4; }
    if ((value & 0xC0) == 0) { n += 2; value <<= 2; }
    return (value & 0x80)? n: (n + 1);
}

inline int numberOfLeadingBits(uint8 value) {
    if (value == 0xFF) return 8;
    int n = 0;
    if ((value & 0xF0) == 0xF0) { n += 4; value <<= 4; }
    if ((value & 0xC0) == 0xC0) { n += 2; value <<= 2; }
    return (value & 0x80) ? (n + 1) : n;
}

inline int numberOfSignificantBits(uint32 value) {
    int n = 1;
    if (value & 0xFFFF0000U) { n += 16; value >>= 16; }
    if (value & 0x0000FF00U) { n +=  8; value >>=  8; }
    if (value & 0x000000F0U) { n +=  4; value >>=  4; }
    if (value & 0x0000000CU) { n +=  2; value >>=  2; }
    return (value & 0x00000002U)?  (n + 1): n;
}

inline uint64 bswap64(uint64 v) {
    asm ("bswapq %0" : "=r" (v) : "0" (v));
    return v;
}

inline uint32 bswap32(uint32 v) {
    asm ("bswapl %0" : "=r" (v) : "0" (v));
    return v;
}

} // namespace NumberUtil
